What are the current prices and wavelengths for UV diodess ?

Down to about 395nm (which is deep purple, more or less, but well capable of
inflicting UV-style fluorescence and such in most long-wave UV materials),
you're looking at less than $3 per LED.  I bought some from Hong Kong
without any problems:

        http://shop.auctionwatch.com/ledcenter/

BillW

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